A hidden greenhouse can work if you keep the envelope as quiet as possible. Use a low‑profile frame, like a steel lattice that blends with the surrounding structure, and cover it with a translucent, matte panel that diffuses light. For light, run solar concentrators or fiber‑optic bundles from a discreet source outside the perimeter; they feed the plants without a visible window. Airflow is controlled through a series of ducted vents that draw in ambient air through a silent exhaust and return it back through a heat‑exchange manifold. Keep all moving parts powered by a small, quiet motor and shield any noise. In short, the greenhouse should be a silent, invisible layer that provides light and air via controlled, low‑profile systems.